i use biobizz light mix 4:2:1 with perlite and vermiculight.i did try plagron light the 50L bag was a few kgs heavier than the biobizz,seemed to have quiet a bit of sand in it,even with the perlite it was a bit claggy.john innes number ? was justr the same real sandy/heavy.B&Q full of bits of wood
dont know why i havnt tried regular biobizz
biobizz did have a great website faq's but i think its broke.my next grow im trying out recycling my soil.